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In 2000, a physicist named Michael Elowitz published one of the first synthetic gene circuits, called the "repressilator." By stitching three genes together, he endowed living cells with an artificial rhythm, coaxing them to flash green. Learn how he built it, and even play around with its parameters, in...

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For 50 years, science told us genes were fixed our destiny written at birth. In 2003, the Human Genome Project quietly shattered that belief. What it revealed instead is a discovery in epigenetics that should be taught in every school on Earth: 1. The old model said: you have a gene for anxiety. A gene for depression. A gene for heart disease. A gene for early death. You inherited it from your parents. Your children will inherit it from you. Nothing you do changes it. The Human Genome Project; a 13-year, $3 billion study was supposed to confirm this. Instead, it revealed something no one expected: Humans have roughly 23,000 genes. Less than a roundworm. The "genetic destiny" model collapsed overnight. 2. What emerged in its place was the field of epigenetics, the science of how your environment controls your DNA. The discovery: genes do not determine your life. Signals from the environment turn genes on and off. And the environment that matters most? Your internal environment. Your thoughts. Your emotions. Science now shows that the emotion you sustain for as little as 15 to 20 minutes a day can signal your immune cells to begin producing new proteins. Your emotional state is writing instructions to your DNA. Right now. 3. In Dr. Joe Dispenza's workshops, students measured for gene expression changes after just 4 days. Significant shifts detected. IgA the immune marker increased measurably. New proteins. New enzymes. New hormones. From thought and emotion alone. No drugs. No surgery. No supplements just the mind-body connection in action. 4. This means: The disease your parent had is not your sentence. The anxiety that runs in your family is a pattern not a prophecy. The body you inherited is not the body you're confined to. You are not a victim of your biology. You are the author of it. Every day you choose the emotional signals you flood your cells with and those signals are rewriting the program. 5. The most powerful pharmacy in existence is inside you. You don't need a prescription for it. You need a practice.

🧬Maxpein🧬

168,719 görüntüleme • 24 gün önce

A single E. coli cell, placed on a dish, will become 70 billion cells in just 12 hours. That’s exponential growth. But a new preprint shows that it's possible to engineer E. coli to grow linearly instead, where only one daughter cell continues dividing and the other stops. First, some context. In nature, there is a bacterium called Mycobacterium smegmatis (initially discovered in 1884 in ulcers scraped from syphilis patients.) M. smegmatis is weird because it divides asymmetrically. These cells grow only from one end, and all their cell wall biosynthesis machinery is located on that one end. So when the cell divides, one daughter gets this machinery and the other gets nothing. The daughter that gets the machinery can keep dividing immediately, but the other daughter has to remake all that machinery from scratch, so its growth is delayed. E. coli doesn’t grow like this. When it divides, it pinches in the middle and splits everything evenly. Enzymes, metabolites, and proteins get partitioned more or less randomly between the two daughters. For the new preprint, though, researchers engineered E. coli to behave more like M. smegmatis. Here is how they did it: First, they deleted a gene called cyaA, which encodes an enzyme (adenylate cyclase) that makes a molecule called cAMP. cAMP is SUPER IMPORTANT! It is a nutrient sensor that instructs E. coli to switch on genes that help it digest non-glucose carbon sources when glucose is scarce. Without cAMP, E. coli cells growing on alternative carbon sources will starve; they won’t know how to eat the food. Next, they added back a “split” version of the cyaA gene into the cells. In other words, they split the gene in two so that each half of the enzyme is made separately. Cells can only make cAMP, and thus eat non-glucose carbon sources, if these two halves come together. To facilitate that “coming together,” the researchers also fused the split cyaA proteins to sticky proteins that clump together, and to a fluorescent protein (to make it easy to track these molecules in the cell.) So now some interesting things start to happen if you grow E. coli on a growth medium lacking glucose. As the cell grows, its cyaA “halves” start clumping together into a giant ball. Inside the aggregate, the two enzyme halves come together and make cAMP. And when the cell gets big enough and divides, the clump of cyaA RANDOMLY goes to either daughter cell #1 or #2. The daughter that gets the aggregate (called PA+ in this paper) can keep dividing. The daughter that doesn’t (PA–) cannot. It still grows a few times — about four divisions — because it inherits some leftover cAMP from its mother. But after that, the metabolite is diluted away, and the cell stops growing. PA+ cells went through about 23 divisions on average before their aggregate decayed. And the population of cells, as a whole, grew linearly. This paper is cool because there are many applications where exponential growth is too unpredictable and, perhaps, unsafe. If you want to engineer bacteria to deliver drugs, clean up waste, or live in the gut, you don’t want them to double uncontrollably. This paper shows you can make them expand in a controlled, linear way. Alas, mutations could break this whole engineered system. A mutation that restores cyaA, for example, would give cells a new way to make cAMP. Mutations that make the aggregates split between daughters would break the asymmetry, too. But still, I really enjoy proof-of-concept engineering papers like this.

Niko McCarty.

58,094 görüntüleme • 1 yıl önce